Formula for average force?

  1. [SOLVED] Formula for average force?

    In a ballistics test at the police department, Officer Rios fires a 6.0 g bullet at 350 m/s into a container that stops it in 1.8 ms. What is the average force that stops the bullet?

    can anyone help me to do this? or just give me the formula? The teacher gave us the right answer and it's -1.2 x 10^3N
    Last edited by a moderator: Dec 18, 2007
  2. jcsd
  3. nicksauce

    nicksauce 1,275
    Science Advisor
    Homework Helper

    The average force is the change in momentum divided by the change in time.
  4. This is just an impulse-momentum theorem problem. Impulse = Change in momentum. Impulse is F*delta t (t=time of impact) and change in momentum is just final momentum - initial momentum. Good luck
  5. delta p= J
    and J= F(delta t)


    delta p=6.0g(350m/s)
    delta p=2100

    is that the same thing as 1.2x10^3?
  6. cristo

    cristo 8,386
    Staff Emeritus
    Science Advisor

    It would be rounded to 1.2x10^3, yes.
  7. thank you so much guys!
  8. cristo

    cristo 8,386
    Staff Emeritus
    Science Advisor

    You're welcome (I'll speak on behalf of the people that actually helped you! :smile:)
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